Speaker: Dr. Arnold Uhl

Company: LUM GmbH

Title: From Dispersibility via Stability to the Secrets of Sediments

Language: German

Abstract:

One technology realized with two complementary physical approaches results in the ideal combination for analytics in product formulation and testing of cosmetics, home and personal care products, based on emulsions and suspensions. The focus of this presentation is on formulations containing titanium dioxide, iron oxides, zinc oxide or other inorganic ingredients. It introduces Space and Time resolved Extinction Profiles (STEP-Technology) with multiple energy sources as applied in a three-step procedure:
1. Characterization of dispersibility and sample homogeneity by X-radiation
2. Accelerated stability testing for all kind of emulsions and suspension by optical wavelengths
3. Understanding of concentration gradients in inorganic sediments, detection of inorganic particles in supernatants by X-radiation.

The formulation in original concentration is filled into one sample cell and undergoes three independent subsequent measurements, after filling, during accelerated separation and after accelerated separation. With the available observation by naked eye a matrix of four different information is obtained, which allows for a comprehensive understanding of the physical separation behaviour of formulations.

In the first step, X-ray transmission data allow for the identification of local particle concentration hotspots, which differentiate a non-homogeneous from a homogeneous formulation. Naked eye or optical wavelengths will detect constant signals concluding all are homogeneous.
Optical wavelengths allow for the direct access to the separation kinetics in the second step, comparable to visual observation. Due to the market demands cosmetics and HPC products are typically formulated stable and very stable against separation, so that here the procedures to accelerate the evaluation of long-term stability (ISO/TR 13097) apply.
Naked eye and optical wavelengths often detect in sediments a constant signal, concluding a homogeneous sediment, which might not be the case. The final step, the evaluation of the separated phases by X-radiation, reveals again the secrets, e.g., in terms of concentration gradients in sediments.